Credential authentication for mobile users

ABSTRACT

Methods, systems, and computer program products for authenticating a mobile client that may have an input system optimized for numeric input. A mobile gateway receives authentication credentials from a mobile client and uses an authentication filter to map the authentication credentials according to pre-established criteria. The authentication filter may change the domain name, the username, or both. Then, the mapped authentication credentials are sent to a network that includes the content server being accessed. Any access privileges granted to the mobile client are based on the mapped authentication credentials. The mobile gateway may be configured to accept connections only from known servers. Mobile authentication credentials may be maintained in one or more domains, possibly having a trust relationship, or may be stored in a separately administered credential database.

BACKGROUND OF THE INVENTION

[0001] 1. The Field of the Invention

[0002] The present invention relates to authentication credentials. Morespecifically, the present invention relates to methods, systems, andcomputer program products for authenticating a mobile client that mayhave an input system optimized for numeric input.

[0003] 2. Background and Related Art

[0004] Content stored on networks often is protected for a number ofreasons. For example, content may include proprietary technology thatprovides a business with a competitive advantage. Many employersconsider at least some portion of their personnel information private orconfidential. It may be important to protect certain vital content, suchas customer orders, from corruption or loss. Whether the motivation isto insure confidentiality or privacy, to prevent the corruption or lossof content, or to secure sensitive information, access to computernetworks usually is governed through authentication credentials, such asa username and password for a particular system or domain.

[0005] However, authentication credentials for a computer network may becompromised in a number of ways, including brute force attacks,monitoring network traffic, and gaining access to third-party systemsthat store authentication credentials. In a brute force attack, a largenumber of potential authentication credentials, perhaps all possiblecombinations, are submitted to a computer network. For example, afour-digit PIN could be discovered by submitting the numbers from 0000to 9999. Although submitting ten thousand numbers may seem like asignificant task, for computers the imposition is minimal at best.

[0006] A common defense to brute force attacks is to increase the numberof possibilities that must be submitted. Each added digit increases thenumber of potential selections by a factor of ten. If letters areavailable in addition to numbers, each character represents a factor ofthirty-six. Including upper and lower case letter increases the weightof each character to sixty-two. For maximum protection, punctuation maybe added to numbers and letters, arriving at a familiar one hundred andone possible choices for each character. (Typical English keyboards soldin the United States are described as 101 keyboards, indicating thenumber of printable characters that are supported.) Even if somecharacters are not allowed, with about one hundred options for each offour characters, the number of distinct combinations approaches 100million, a significant improvement over the ten thousand combinationsoffered by a four-digit PIN.

[0007] Because arbitrary combinations of numbers, letters, andpunctuation are difficult to remember, words, dates, acronyms, and thelike, may help to keep authentication credentials familiar. Attackersexploit this weakness by employing a type of brute force attack,typically known as a dictionary attack. There is no need to try allcombinations of letters or numbers; rather, only combinations that makesense as words, acronyms, or dates are submitted. Limiting the attack toa “dictionary” may reduce our 100 million improvement back to the rangeof ten or twenty thousand, and even less if only relatively common wordsare considered.

[0008] To reduce the threat posed by dictionary attacks, networkadministrators may impose policies regarding authentication credentials.For example, passwords may be required to include at least one uppercase letter, at least one lower case letter, at least one number, and atleast one punctuation character. In addition, a certain length may bemandated, such as five, six, seven, or eight characters. Because longpasswords are more difficult to remember, specifying much more thaneight characters may be counter productive because the passwords will bewritten down rather than memorized, allowing for authenticationcredentials to be compromised if the written password is everdiscovered. For example, an all too common occurrence in a financialcontext is storing a PIN with its corresponding charge or debit card.Any value to the PIN is all but lost if the PIN must be written to beremembered. Similar issues exist in other environments, particularlyregarding access to computer networks.

[0009] Recently, there has been an increasing demand for access tocomputer networks, and the content they may offer, using mobile clients.Due to their convenient size and utility, telephones are among of themost widely-used mobile clients. However, some mobile clients, such astelephones, have input systems that are optimized for numeric input.While letters and punctuation may be available, it is often quitecumbersome for most users to enter any characters other than numbers. Asdescribed above, allowing authentication credentials that only containdigits makes a computer network vulnerable to brute force attacks.

[0010] Furthermore, third parties may be involved in providing mobileaccess to content. For example, telephones may connect to a wirelessapplication protocol (“WAP”) server in reaching a desired network orcontent server. In many circumstances, the WAP server and the networkwill be entirely unrelated. Businesses may be unwilling or unable tobear the expense of offering mobile access to their network, whereastelephone carriers will be able to use WAP servers as a revenue streamthrough increased airtime.

[0011] Intermediate servers represent a security risk, because wirelessprotocols may not provide for secure end-to-end connections. Secureconnections may be limited to each hop, such as a secure connectionbetween a telephone and a WAP server, and a secure connection betweenthe WAP server and the network being accessed. As a result, the WAPserver will contain unencrypted content. For example, the telephone mayenter authentication credentials that are encrypted during transit tothe WAP server. The WAP server decrypts the authentication credentialsand then re-encrypts the authentication credentials based on the secureprotocol used in communicating with the network. If the WAP server iscompromised, an attacker may be able to acquire authenticationcredentials that will allow access to any network that the mobileclients have accessed. Furthermore, to reduce the amount of informationthat must be remembered, mobile clients may use the same authenticationcredentials for other networks that do not provide mobile access, makingthose other networks vulnerable to attack as well.

[0012] Although it may be unlikely that an intermediate server will becompromised, the problem for the network is that the risk may bedifficult to quantify. Security measures at the intermediate server aredetermined, implemented, monitored, and controlled, by whomever isresponsible for the intermediate server. For some networks, the riskfrom numeric authentication credentials, coupled with uncertainty as tothe extent of security provided by an intermediate server, will be toogreat, and mobile access will be prohibited.

SUMMARY OF THE INVENTION

[0013] These and other problems are overcome by the present invention,which is directed toward authentication based on relatively weakcredentials, such as passwords with few characters or passwords withlimited selections for each character. For example, one client may havean input system optimized for numeric input and therefore use numericonly passwords, whereas another client may user relatively shortpasswords. In general, the present invention may be used to map one setof authentication credentials to another set of authenticationcredentials. A gateway receives authentication credentials from theclient and uses an authentication filter to map the authenticationcredentials according to pre-established criteria. The authenticationfilter may change the domain name, the username, or both. For example,one domain name may be substituted for another, or a suffix may be addedto the username. Then the mapped authentication credentials are sent tothe network that includes the content server being accessed. Any accessprivileges granted to the client are based on the mapped authenticationcredentials.

[0014] The gateway allows for authentication credentials that arespecific to client access through the gateway, without disclosinginformation about the network to which clients connect. If a client'scredentials are compromised, attempts to authenticate with thecredentials that do not involve the gateway will fail because thespecified domain name, username, or both, do not exist on the network.Furthermore, the gateway may be configured to accept connections onlyfrom known third party servers. As a result, any authenticationcredentials that may be discovered by an attacker are limited to use ina gateway context.

[0015] By defining authentication credentials that are specific toclient access through the gateway, network administrators are able tobalance an appropriate level of access permissions with the increasedlevel of risk that results from weak credentials, such as numericpasswords. Rather than granting the same level of access that a userwould enjoy using other authentication credentials, such as whenauthenticating with an office computer over an internal networkconnection, gateway authentication credentials can be restricted toinsure minimal exposure if compromised. For example, gatewayauthentication credentials may be limited to the network resources of asingle user, such as the user's email account, a default logindirectory, etc., whereas other authentication credentials might allowthe user access to a large number of network resources that areordinarily shared among a number of users, including servers,directories, databases, etc.

[0016] The gateway also facilitates management of gateway authenticationcredentials. The domain names and/or usernames may be updated withoutimposing hardship on the clients. For example, if it appears that adomain has been compromised, a new domain may be created or new accountsin a domain may be created and the gateway configured accordingly.Gateway authentication credentials may be associated with otherauthentication credentials to identify potential resources that clientsmay access, with specific access permissions granted as appropriate. Inother words, gateway authentication credentials would not grantpermissions greater than those provided for in the other authenticationcredentials.

[0017] A trust relationship may be established between variousauthentication credentials and corresponding domains. The trustrelationship defines specific areas of trust. For example, one domainmay trust the authentication credentials in another domain for delegateaccess privileges, but not for other, more sensitive privileges, such asadministrator privileges. Defining a trust relationship offers anadditional level of control over mobile access privileges because itprevents mobile authentication credentials from superceding otherauthentication qualifications.

[0018] Additional features and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by the practice of the invention. Thefeatures and advantages of the invention may be realized and obtained bymeans of the instruments and combinations particularly pointed out inthe appended claims. These and other features of the present inventionwill become more fully apparent from the following description andappended claims, or may be learned by the practice of the invention asset forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to describe the manner in which the above-recited andother advantages and features of the invention can be obtained, a moreparticular description of the invention briefly described above will berendered by reference to specific embodiments thereof which areillustrated in the appended drawings. Understanding that these drawingsdepict only typical embodiments of the invention and are not thereforeto be considered as limiting its scope, the invention will be describedand explained with additional specificity and detail through the use ofthe accompanying drawings in which:

[0020]FIG. 1 illustrates an exemplary system that provides a suitableoperating environment for the present invention;

[0021]FIG. 2 is a block diagram showing a network with separate domainsfor mobile and other authentication credentials;

[0022]FIG. 3 is a block diagram showing a network with a single domainfor mobile and other authentication credentials; and

[0023]FIG. 4 illustrates an exemplary method for authenticating a mobileclient through a mobile gateway.

DETAILED DESCRIPTION OF THE INVENTION

[0024] The present invention extends to methods, systems, and computerprogram products for authenticating clients. A gateway mapsauthentication credentials received from a client and sends the mappedauthentication credentials to a network that includes the resources theclient desires to access. Authentication credentials identify aparticular client and determine the resources the client is authorizedto access, including the types of access permitted.

[0025] Authentication credentials often include a username and passwordfor one or more domains. Other types of information, including biometricattributes (e.g., fingerprints) and hardware keys (e.g., smartcards),may be used as well. The present invention is not limited to anyparticular type of authentication credentials. Authenticationcredentials ordinarily apply to a group or collection of one or moreresources, often referred to as a domain. Domains facilitate resourceadministration by allowing resources to be managed as a single unit,with common rules and procedures. More generally, the term “domain”describes a logical grouping of resources, wherein the grouping may beindependent of how resources are interconnected. A single network mayhave one or more domains and a single domain may include one or morenetworks.

[0026] At times, authentication credentials may be described as weak orshort. As used in this application, however, weak and short should beinterpreted as a comparative, rather than absolute, terms. Weak and/orshort authentication credentials are weak and/or short only in thatstronger and/or longer authentication credentials are possible and maybe desirable. For example, a four-digit password is weak and short incomparison to a five-digit password. Similarly, a five-digit password isweak, although not short, in comparison to a five-character alphanumericpassword. In its most general sense, the present invention involvessubstituting one set of authentication credentials for another. Thespecific examples discussed below merely identify exemplary environmentsor embodiments for practicing the present invention and should not beinterpreted as necessarily limiting its scope.

[0027] The term “client” may be used to describe individuals, devices,computers, systems, etc., either alone or in combination, that accesscomputer resources. The term “server” describes a provider of computerresources, and likewise includes devices, computers, systems, etc.Depending on the circumstances, a server in one setting may be a clientin another, and likewise, a client in one setting may be a server atother times. The term network describes interconnected resources, andencompasses a wide range of configurations, including a single resource,such as a computer, storage system, printer, file server, etc., thatallows connections with clients and/or any other resource.

[0028] Each of the foregoing terms should be accorded the widestpossible interpretation. Those of skill in the art may recognize that,in a particular context, certain terms may acquire a more specific oralternate meaning. It should be noted, therefore, that the followingdetailed description is offered to present exemplary implementations andis not intended to limit the scope of the present invention. Theembodiments of the present invention may comprise a special purpose orgeneral purpose computer including various computer hardware, asdiscussed in greater detail below.

[0029] Embodiments within the scope of the present invention alsoinclude computer-readable media for carrying or havingcomputer-executable instructions or data structures stored thereon. Suchcomputer-readable media can be any available media which can be accessedby a general purpose or special purpose computer. By way of example, andnot limitation, such computer-readable media can comprise RAM, ROM,EEPROM, CD-ROM or other optical disk storage, magnetic disk storage orother magnetic storage devices, or any other medium which can be used tocarry or store desired program code means in the form ofcomputer-executable instructions or data structures and which can beaccessed by a general purpose or special purpose computer. Wheninformation is transferred or provided over a network or anothercommunications connection (either hardwired, wireless, or a combinationof hardwired or wireless) to a computer, the computer properly views theconnection as a computer-readable medium. Thus, any such a connection isproperly termed a computer-readable medium. Combinations of the aboveshould also be included within the scope of computer-readable media.Computer-executable instructions comprise, for example, instructions anddata which cause a general purpose computer, special purpose computer,or special purpose processing device to perform a certain function orgroup of functions.

[0030]FIG. 1 and the following discussion are intended to provide abrief, general description of a suitable computing environment in whichthe invention may be implemented. Although not required, the inventionwill be described in the general context of computer-executableinstructions, such as program modules, being executed by computers innetwork environments. Generally, program modules include routines,programs, objects, components, data structures, etc. that performparticular tasks or implement particular abstract data types.Computer-executable instructions, associated data structures, andprogram modules represent examples of the program code means forexecuting steps of the methods disclosed herein. The particular sequenceof such executable instructions or associated data structures representexamples of corresponding acts for implementing the functions describedin such steps.

[0031] Those skilled in the art will appreciate that the invention maybe practiced in network computing environments with many types ofcomputer system configurations, including personal computers, hand-helddevices, multi-processor systems, microprocessor based or programmableconsumer electronics, network PCs, minicomputers, mainframe computers,and the like. The invention may also be practiced in distributedcomputing environments where tasks are performed by local and remoteprocessing devices that are linked (either by hardwired links, wirelesslinks, or by a combination of hardwired or wireless links) through acommunications network. In a distributed computing environment, programmodules may be located in both local and remote memory storage devices.

[0032] With reference to FIG. 1, an exemplary system for implementingthe invention includes a general purpose computing device in the form ofa conventional computer 20, including a processing unit 21, a systemmemory 22, and a system bus 23 that couples various system componentsincluding the system memory 22 to the processing unit 21. The system bus23 may be any of several types of bus structures including a memory busor memory controller, a peripheral bus, and a local bus using any of avariety of bus architectures. The system memory includes read onlymemory (ROM) 24 and random access memory (RAM) 25. A basic input/outputsystem (BIOS) 26, containing the basic routines that help transferinformation between elements within the computer 20, such as duringstart-up, may be stored in ROM 24.

[0033] The computer 20 may also include a magnetic hard disk drive 27for reading from and writing to a magnetic hard disk 39, a magnetic diskdrive 28 for reading from or writing to a removable magnetic disk 29,and an optical disk drive 30 for reading from or writing to removableoptical disk 31 such as a CD-ROM or other optical media. The magnetichard disk drive 27, magnetic disk drive 28, and optical disk drive 30are connected to the system bus 23 by a hard disk drive interface 32, amagnetic disk drive-interface 33, and an optical drive interface 34,respectively. The drives and their associated computer-readable mediaprovide nonvolatile storage of computer-executable instructions, datastructures, program modules and other data for the computer 20. Althoughthe exemplary environment described herein employs a magnetic hard disk39, a removable magnetic disk 29 and a removable optical disk 31, othertypes of computer readable media for storing data can be used, includingmagnetic cassettes, flash memory cards, digital video disks, Bernoullicartridges, RAMs, ROMs, and the like.

[0034] Program code means comprising one or more program modules may bestored on the hard disk 39, magnetic disk 29, optical disk 31, ROM 24 orRAM 25, including an operating system 35, one or more applicationprograms 36, other program modules 37, and program data 38. A user mayenter commands and information into the computer 20 through keyboard 40,pointing device 42, or other input devices (not shown), such as amicrophone, joy stick, game pad, satellite dish, scanner, or the like.These and other input devices are often connected to the processing unit21 through a serial port interface 46 coupled to system bus 23.Alternatively, the input devices may be connected by other interfaces,such as a parallel port, a game port or a universal serial bus (USB). Amonitor 47 or another display device is also connected to system bus 23via an interface, such as video adapter 48. In addition to the monitor,personal computers typically include other peripheral output devices(not shown), such as speakers and printers.

[0035] The computer 20 may operate in a networked environment usinglogical connections to one or more remote computers, such as remotecomputers 49 a and 49 b. Remote computers 49 a and 49 b may each beanother personal computer, a server, a router, a network PC, a peerdevice or other common network node, and typically include many or allof the elements described above relative to the computer 20, althoughonly memory storage devices 50 a and 50 b and their associatedapplication programs 36 a and 36 b have been illustrated in FIG. 1. Thelogical connections depicted in FIG. 1 include a local area network(LAN) 51 and a wide area network (WAN) 52 that are presented here by wayof example and not limitation. Such networking environments arecommonplace in office-wide or enterprise-wide computer networks,intranets and the Internet.

[0036] When used in a LAN networking environment, the computer 20 isconnected to the local network 51 through a network interface or adapter53. When used in a WAN networking environment, the computer 20 mayinclude a modem 54, a wireless link, or other means for establishingcommunications over the wide area network 52, such as the Internet. Themodem 54, which may be internal or external, is connected to the systembus 23 via the serial port interface 46. In a networked environment,program modules depicted relative to the computer 20, or portionsthereof, may be stored in the remote memory storage device. It will beappreciated that the network connections shown are exemplary and othermeans of establishing communications over wide area network 52 may beused.

[0037] The block diagram of FIG. 2 shows network 210 with separatedomains, mobile domain 240 and other domain(s) 230, for managing mobileand other authentication credentials, respectively. Mobile domain 240may be recognized generally by network 210 or may be used only inproviding access to content server 220. Other domain(s) 230 includesusername 232, identifying Neil as a user, with a password 234 ofA1(b)c5. (Note that the use of upper and lower case characters, numbers,and punctuation, provides a significant defense against brute forceattacks.) Mobile domain 240 includes username 242, identifying Neil-m asa user, with a numeric password 244 of 1234. As indicated by references212 and 214, both Neil and Neil-m have access permissions for contentserver 220.

[0038] Because mobile domain 240 is separate from other domain(s) 230,it is not necessary for username 242 and username 232 to be different.Either separate usernames or separate domain names is sufficient forproviding authentication credentials that are specific to a mobileclient. In practice, administration of the two domains may be simplifiedif usernames are shared. For example, a trust relationship may beestablished between the two domains. The extent of the trustrelationship between the domains depends on the circumstances of aparticular implementation, but the mobile domains would be trusted withrespect to some minimal level of access permissions, such as delegatepermissions in an email context. The different usernames, however, aidbelow in distinguishing between comments referring to other domain(s)230 and comments that refer to mobile domain 240. The distinctusernames, Neil and Neil-m, therefore, will be retained throughout theremaining discussion of FIG. 2 for the sake of clarity. Note that FIG. 3focuses attention on the use of a single domain with differentusernames.

[0039] To account for the increased risk associated with mobile clients,the access permissions granted through mobile domain 240 are limited ascompared to those granted by other domain(s) 230. For example, ifcontent server 220 provides email resources, Neil may have all accessrights for a particular email account, whereas Neil-m may be grantedonly certain delegate access privileges. Furthermore, Neil also may haveaccess privileges to other resources that are part of other domain(s)230, whereas Neil-m's access privileges extend only to content server220.

[0040] Access privileges may apply to one or multiple clients. Forexample, the owner or administrator of a resource may have one set ofaccess privileges, certain groupings or domains may have another set ofaccess privileges, and all others may have a default set of accessprivileges. Those of skill in the art will recognize that a variety ofschemes for specifying access privileges exist and that others may bedeveloped in the future. It should be noted that the present inventionis not limited to any particular form of access privileges. Rather, thepresent invention recognizes that it may be desirable to provideseparate access privileges for mobile clients, and provides the relevanttechnology for doing so, independent of the underlying implementationaccess privileges.

[0041] If the authentication credentials associated with Neil-m werecompromised, only the resources available to a single mobile clientwould be accessible. For email resources, this probably will includeonly the mobile client's mailbox. In contrast, compromising theauthentication credentials associated with Neil, are likely to yieldmuch wider access privileges to resources of network 210 that areprobably shared by various clients.

[0042] Alternatively mobile domain 240 may be a separately administeredcredential database that is only used in providing access to contentserver 220. In this case, mobile domain 240 is not a domain in the samesense that other domain(s) 230 is a domain. The separately administeredcredential database could not be used for direct access of resourcesthat are part of network 210. Rather, content server 220 may beconfigured to verify authentication credentials included within thiscredential database. Once verified, a shared account in a domain, suchas other domain(s) 230, would be used in accessing content server 220.As above, if the authentication credentials for Neil-m were compromised,only the resources available to a single mobile client would be at risk,such as the client's mailbox. However, if the shared account werecompromised, resources associated with all mobile clients would be atrisk.

[0043] Turning now to the flow of authentication credentials from any ofvarious mobile clients to network 210, phone 280 provides authenticationcredentials to WAP server 270 over connection 296. Although a textualusername (Neil) is shown in FIG. 2, the username is ordinarily stored atthe phone so it does not need to be entered each time a request forcontent is made. Connection 296 may be encrypted, using a protocol suchas wireless transport layer security (“WTLS”), to protect contentexchanged between phone 280 and WAP server 270. WAP server 270 decryptsthe authentication credentials and sends them to mobile gateway 250 overconnection 294. Like connection 296, connection 294 may encrypt theauthentication credentials using a protocol such as secure sockets layer(“SSL”). Typically, WAP server 270 operates as a protocol translatorbetween the wireless protocols of mobile clients and the wirelineprotocols used in communicating with mobile gateway 250. Theauthentication credentials are subject to attack at the WAP serverbecause, at least for a time, they are unencrypted. Furthermore, becausethe authentication credentials are likely to include relative shortnumeric portions, such as a numeric password or PIN, the authenticationcredentials are vulnerable to brute force attacks.

[0044] Mobile gateway 250 includes an authentication filter 260 that isused in mapping received authentication credentials. Authenticationfilter 260 includes two components, domain identifier 266 and usernamemodifier 262. The domain identifier 266 specifies the domain thatnetwork 210 will use in processing authentication credentials. In FIG.2, the domain identifier is Mobile. Changing a domain name in accordancewith domain identifier 266 includes substituting one domain for another(replacing a domain specified by a mobile client with domain identifier266), altering a domain name (making a change to a domain specified by amobile client), and adding a domain where none was specified (addingdomain identifier 266 where a mobile client did not specify a domain),etc. The username modifier 262 includes a username box 262 a and asuffix 262 b. Username box 262 a is simply a placeholder for allusernames, whereas the mobile gateway adds suffix 262 b to usernames.Mobile gateway 250 sends network 210 mapped authentication credentialsover connection 292, using encryption as appropriate.

[0045] Network 210 processes the authentication credentials it receivesas described above. Note that mobile gateway 250 identifies both aseparate mobile domain 240 and adds a username suffix. If the usernameNeil, and password 1234 are entered at phone 280, mobile gateway changesthe username to Neil-m and sends the authentication credentials tomobile domain 240 for processing. Because a username Neil-m, with apassword of 1234, exists in mobile domain 240, phone 280 will be grantedthe access privileges that are associated with Neil-m. Ordinarily, onlya separate mobile domain, such as mobile domain 240, or a usernamesuffix is needed to provide authentication credentials that are specificto a mobile client.

[0046] The block diagram of FIG. 3 shows a network with a single domain,corporate domain 330, for both mobile and other authenticationcredentials. A username 332 of Mike with a password 334 of X9(y)z3 isdefined in corporate domain 330 for determining access privileges to theresources, such as content server 320, of network 310. A mobile client,with a username 342 of Mike-m and a password 344 of 5678 is also definedin corporate domain 330. Note that the present invention does notrequire that any particular suffix be added to usernames. Furthermore,the present invention does not necessarily require changing usernames byadding a suffix. Usernames may be changed by adding a prefix, insertingcharacters into the middle of a username, substituting all or a portionof a username for another portion or username, deleting characters froma username, etc.

[0047] Similar to the description with reference to FIG. 2, and turningnow to the flow of authentication credentials from any of various mobileclients to network 310, phone 380 provides authentication credentials toWAP server 370 over connection 396, using WTLS. WAP server 370 decryptsthe authentication credentials received over connection 396 andre-encrypts the authentication credentials for SSL connection 394. Atmobile gateway 350, authentication filter 360 adds suffix 362 b tousernames 362 a, as indicated by reference 362. Mobile gateway 350 setsthe applicable domain 366 for the received authentication credentials toCorporate.

[0048] If the username Mike, and password 5678 are entered at phone 380,mobile gateway changes the username to Mike-m and sends theauthentication credentials to corporate domain 330 for processing.Because a username Mike-m, with a password of 5678, exists in corporatedomain 330, phone 380 will be granted the access privileges that areassociated with Mike-m. Here, only a single domain, such as corporatedomain 330, is needed to provide authentication credentials that arespecific to a mobile client.

[0049] One drawback to the single domain implementation is that policiesand procedures for authentication credentials are often set on a domainbasis. That is, corporate domain 330 may be set to require at least oneupper case letter, at least one lower case letter, a number, and apunctuation character, in all passwords. By having Mike-m in corporatedomain 330, password 344 would be subject to these requirements, andtherefore, an all-numeric password, such as 5678, may not be allowed.

[0050] It should also be noted that authentication filter 360 is capableof making whatever changes to authentication credentials that areappropriate for the type and format of authentication credentialsimplemented by network 310, content server 320, and/or corporate domain330. As reference 312 shows, content server 320 depends on corporatedomain 330 for determining access privileges. A particularimplementation of authentication credentials, however, is notnecessarily limited by the present invention. Any changes that mobilegateway 350 makes need only be proper for the authentication credentialsthat are expected by network 310, content server 320, and/or corporatedomain 330. Where a separately administered authentication credentialdatabase provides access to resources, the mapping performed by a mobilegateway may be specific to the separate credential database, even thoughthose mappings would not be appropriate for network 310 or anyassociated domains.

[0051] Turning now to FIG. 4, an exemplary method for authenticating amobile client through a mobile gateway is illustrated. A step foraltering (410) authentication credentials may include the acts ofdefining (412) an authentication filter and mapping (414) any receivedauthentication credentials. Mapping may include changing the domainname, username, or otherwise modifying the authentication credentials.One domain name may be substituted for another and usernames may have asuffix added.

[0052] A step for identifying (420) a mobile client may include the actsof receiving (422) authentication credentials from a mobile client andsending (424) the mapped authentication credentials to a networkproviding the resources that will be requested by the mobile client. Thesteps of altering (410) authentication credentials and identify (420) amobile client are intertwined to indicate that the acts associated withthe steps are not necessarily performed in any particular order. A stepfor accessing (430) content provided by the network may include the actsof receiving (432) a request for content, sending (434) the request tothe network, receiving (436) the requested content, and sending (438)the requested content to the mobile client.

[0053] The present invention may be embodied in other specific formswithout departing from its spirit or essential characteristics. Thedescribed embodiments are to be considered in all respects only asillustrative and not restrictive. The scope of the invention is,therefore, indicated by the appended claims rather than by the foregoingdescription. All changes which come within the meaning and range ofequivalency of the claims are to be embraced within their scope.

What is claimed and desired to be secured by United States LettersPatent is:
 1. In a computerized system that includes one or more clientsaccessing a gateway and content server that are part of a network,wherein access to the content server requires authenticationcredentials, the network maintaining gateway authentication credentialsthat specify one or more access privileges tailored to access throughthe gateway, a method of authenticating a client comprising a gatewayperforming the acts of: defining an authentication filter that mapsauthentication credentials received from clients according topre-established criteria; receiving authentication credentials from aclient; mapping the received authentication credentials based on thepre-established criteria, the mapped authentication credentials matchinggateway authentication credentials maintained on the network andcorresponding to client access through the gateway; and sending themapped authentication credentials to the network, wherein the client'saccess to the content source is determined from the mappedauthentication credentials.
 2. A method as recited in claim 1 whereingateway authentication credentials and other authentication credentialsare maintained in separate domains, and wherein the act of mapping thereceived authentication credentials includes changing a domain name thatis part of the received authentication credentials.
 3. A method asrecited in claim 2 wherein the act of mapping the receivedauthentication credentials includes replacing the domain name that ispart of the received authentication credentials with another domainname.
 4. A method as recited in claim 1 wherein the gatewayauthentication credentials are maintained in a credential database thatis administered separately from domain authentication credentials andrecognized by the content server only in authenticating client accessthrough the gateway.
 5. A method as recited in claim 1 wherein gatewayauthentication credentials and other authentication credentials share acommon domain, and wherein the act of mapping the receivedauthentication credentials includes changing a username that is part ofthe received authentication credentials.
 6. A method as recited in claim5 wherein the act of mapping the received authentication credentialsincludes adding a suffix to the username.
 7. A method as recited inclaim 5 wherein the act of mapping the received authenticationcredentials includes adding a prefix to the username.
 8. A method asrecited in claim 1 wherein the client includes one or more identifiedwireless application protocol servers providing gateway and contentserver access to one or more other clients, the method furthercomprising the act of accepting authentication credentials only from theone or more identified wireless application protocol servers.
 9. Amethod as recited in claim 1 wherein the gateway authenticationcredentials correspond to other authentication credentials that allowaccess to a content server, and wherein a trust relationship existsbetween the gateway authentication credentials and other authenticationcredentials with respect to one or more access privileges, the methodfurther comprising the acts of: receiving a request for contentavailable at the content server; sending the request to the network;receiving the requested content from the network; and sending thereceived content to the client.
 10. A method as recited in claim 9wherein the content available at the content server comprises emailcontent.
 11. A method as recited in claim 9 wherein the one or moreaccess privileges included within the trust relationship that existsbetween the gateway authentication credentials and the otherauthentication credentials comprise a delegate access permission.
 12. Ina computerized system that includes one or more mobile clients accessinga mobile gateway and content server that are part of a network, whereinaccess to the content server requires authentication credentials thatmay contain a combination of numbers, upper case letters, lower caseletters, and punctuation, and wherein at least some of the mobileclients use relatively short authentication credentials or have an inputsystem that is optimized for numeric input rather than for letters orpunctuation, the network maintaining mobile authentication credentialsthat specify one or more access privileges tailored to mobile clientaccess, a method of authenticating a mobile client comprising a mobilegateway performing steps for: altering authentication credentials toproduce mapped authentication credentials that match mobileauthentication credentials maintained on the network; identifying amobile client to the network using the altered authenticationcredentials; and accessing content provided by the network in accordancewith the access privileges allowed by the mobile authenticationcredentials.
 13. A method as recited in claim 12 wherein the step foraltering authentication credentials comprises the acts of: defining anauthentication filter that maps authentication credentials received frommobile clients according to pre-established criteria; and mapping thereceived authentication credentials based on the pre-establishedcriteria.
 14. A method as recited in claim 12 wherein the step foridentifying a mobile client comprises the acts of: receivingauthentication credentials from a mobile client; and sending mappedauthentication credentials to the network, wherein the mobile client'saccess to the content source is determined from the mappedauthentication credentials.
 15. A method as recited in claim 12 whereinthe step for altering authentication credentials includes changing atleast one of a domain name and a username that are part of theauthentication credentials.
 16. A method as recited in claim 15 whereinchanging at least one of the domain name and a username includes eitheradding a suffix to the username or replacing the domain name withanother domain name.
 17. A method as recited in claim 12 wherein themobile authentication credentials are maintained in a credentialdatabase that is administered separately from domain authenticationcredentials and recognized by the content server only in authenticatingmobile clients.
 18. A method as recited in claim 12 wherein mobileauthentication credentials and other authentication credentials share acommon domain.
 19. A method as recited in claim 12 wherein the mobileclient includes one or more identified wireless application protocolservers providing mobile gateway and content server access to one ormore other mobile clients, the step for identifying a mobile clientcomprising the act of accepting authentication credentials only from theone or more identified wireless application protocol servers.
 20. Amethod as recited in claim 12 wherein the step for accessing contentprovided by the content server comprises the acts of: receiving arequest to access content from the mobile client; sending the request tothe network; receiving the requested content from the network; andsending the received content to the mobile client.
 21. A method asrecited in claim 20 wherein the content is email content.
 22. A methodas recited in claim 12 wherein a trust relationship exists between themobile authentication credentials and other authentication credentialswith respect to one or more access privileges.
 23. A method as recitedin claim 22 wherein the one or more access privileges included withinthe trust relationship that exists between the mobile authenticationcredentials and the other authentication credentials comprise a delegateaccess permission.
 24. In a computerized system that includes one ormore mobile clients accessing a mobile gateway and content server thatare part of a network, wherein access to the content server requiresauthentication credentials that may contain a combination of numbers,upper case letters, lower case letters, and punctuation, and wherein atleast some of the mobile clients use relatively short authenticationcredentials or have an input system that is optimized for numeric inputrather than for letters or punctuation, the network maintaining mobileauthentication credentials that specify one or more access privilegestailored to mobile client access, a computer program product thatimplements a method of authenticating a mobile client, comprising: acomputer readable medium for carrying machine-executable instructionsfor implementing the method; and wherein said method is comprised ofmachine-executable instructions for a mobile gateway performing the actsof: defining an authentication filter that maps authenticationcredentials received from mobile clients according to pre-establishedcriteria; receiving authentication credentials from a mobile client;mapping the received authentication credentials based on thepre-established criteria, the mapped authentication credentials matchingmobile authentication credentials corresponding to the mobile client andmaintained on the network; and sending the mapped authenticationcredentials to the network, wherein the mobile client's access to thecontent source is determined from the mapped authentication credentials.25. A computer program product as recited in claim 24 wherein mobileauthentication credentials and other authentication credentials aremaintained in separate domains, and wherein the act of mapping thereceived authentication credentials includes changing a domain name thatis part of the received authentication credentials.
 26. A computerprogram product as recited in claim 25 wherein the act of mapping thereceived authentication credentials includes replacing the domain namethat is part of the received authentication credentials with anotherdomain name.
 27. A computer program product as recited in claim 24wherein the mobile authentication credentials are maintained in acredential database that is administered separately from domainauthentication credentials and recognized by the content server only inauthenticating mobile clients.
 28. A computer program product as recitedin claim 24 wherein mobile authentication credentials and otherauthentication credentials share a common domain, and wherein the act ofmapping the received authentication credentials includes changing ausername that is part of the received authentication credentials.
 29. Acomputer program product as recited in claim 28 wherein the act ofmapping the received authentication credentials includes adding a suffixto the username.
 30. A computer program product as recited in claim 28wherein the act of mapping the received authentication credentialsincludes adding a prefix to the username.
 31. A computer program productas recited in claim 24 wherein the mobile authentication credentialscorrespond to other authentication credentials that allow access to acontent server, and wherein a trust relationship exists between themobile authentication credentials and other authentication credentialswith respect to one or more access privileges, the method furthercomprising computer-executable instructions for performing the acts of:receiving a request for content available at the content server; sendingthe request to the network; receiving the requested content from thenetwork; and sending the received content to the mobile client.
 32. Acomputer program product as recited in claim 31 wherein the contentavailable at the content server comprises email content.
 33. A computerprogram product as recited in claim 31 wherein the one or more accessprivileges included within the trust relationship that exists betweenthe mobile authentication credentials and the other authenticationcredentials comprise a delegate access permission.
 34. A computerprogram product as recited in claim 24 wherein the mobile clientincludes one or more identified wireless application protocol serversproviding mobile gateway and content server access to one or more othermobile clients, the method further comprising computer-executableinstructions for performing the act of accepting authenticationcredentials only from the one or more identified wireless applicationprotocol servers.